Solution:2

Select A.Id From YourTable A Where A.YourDateTime Between :StartDateTime and :EndDateTime Group By A.Id Having COUNT(A.Id) = 2

Solution:3

I haven't checked William's query but I would seriously consider using what he has over every other. Analytics are da bomb. Anytime you find yourself joining a table back to itself is virtually guaranteed to be an opportunity to use analytics and will out perform the query with one table referenced twice every time.